Let Display#sleep() react to thread interruption

Fix #3059

Author: laeubi

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java

@@ -5231,13 +5231,19 @@ public boolean sleep () {
 	try {
 		addPool();
 		allowTimers = runAsyncMessages = false;
-		NSRunLoop.currentRunLoop().runMode(OS.NSDefaultRunLoopMode, NSDate.distantFuture());
+		/*
+		 * Use a timeout-based approach to allow checking for thread interruption.
+		 * Sleep for a maximum of 50 milliseconds at a time, similar to GTK.
+		 */
+		do {
+			NSRunLoop.currentRunLoop().runMode(OS.NSDefaultRunLoopMode, NSDate.dateWithTimeIntervalSinceNow(0.05));
+		} while (synchronizer.isMessagesEmpty() && !thread.isInterrupted());
 		allowTimers = runAsyncMessages = true;
 	} finally {
 		removePool();
 	}
 	sendPostExternalEventDispatchEvent ();
-	return true;
+	return !thread.isInterrupted();
 }
 
 int sourceProc (int info) {

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java

@@ -5633,11 +5633,11 @@ public boolean sleep () {
 			OS.g_main_context_check (context, max_priority [0], fds, nfds);
 			OS.g_main_context_release (context);
 		}
-	} while (!result && synchronizer.isMessagesEmpty() && !wake);
+	} while (!result && synchronizer.isMessagesEmpty() && !wake && !thread.isInterrupted());
 	wake = false;
 	if (!GTK.GTK4) GDK.gdk_threads_enter ();
 	sendPostExternalEventDispatchEvent ();
-	return true;
+	return !thread.isInterrupted();
 }
 
 /**

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Display.java

@@ -1407,6 +1407,47 @@ public void run() {
 	}
 }
 
+@Test
+@DisabledOnOs(value = org.junit.jupiter.api.condition.OS.WINDOWS, disabledReason = "Windows uses WaitMessage() which does not support timeout-based interruption checking")
+public void test_sleep_respondToInterrupt() {
+	final Display display = new Display();
+	Shell shell = new Shell(display);
+	try {
+		shell.open();
+		Thread uiThread = Thread.currentThread();
+
+		// Start a thread that will interrupt the UI thread after 1 second
+		Thread interrupter = new Thread(() -> {
+			try {
+				Thread.sleep(1000);
+				uiThread.interrupt();
+			} catch (InterruptedException e) {
+				// Ignore
+			}
+		});
+		interrupter.start();
+
+		// Event loop with timeout to prevent hanging if sleep() never responds to interrupt
+		long deadline = System.currentTimeMillis() + 5000;
+		while (!shell.isDisposed() && System.currentTimeMillis() < deadline) {
+			if (!display.readAndDispatch()) {
+				boolean hasMoreWork = display.sleep();
+				// When interrupted, sleep() returns false and interrupt flag is preserved
+				if (!hasMoreWork && uiThread.isInterrupted()) {
+					// Success! Clean up and return
+					Thread.interrupted(); // clear flag
+					return;
+				}
+			}
+		}
+		// If we get here, the test failed
+		fail("sleep() did not respond to thread interruption within timeout");
+	} finally {
+		shell.dispose();
+		display.dispose();
+	}
+}
+
 @Test
 public void test_syncExecLjava_lang_Runnable() {
 	final Display display = new Display();